* The IAU defines planets: The International Astronomical Union (IAU) is the organization that sets the standards for astronomical naming and classifications. They officially define what constitutes a planet, and they keep track of all the objects in our solar system that meet those criteria.

* We know all the planets (according to the IAU): The IAU recognizes eight planets in our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. They also have a separate classification for "dwarf planets", of which Pluto is the most famous example.

* There could be undiscovered planets: It's possible that there are planets out there beyond Neptune that we haven't yet discovered. However, the IAU wouldn't officially recognize them as planets until they were observed and confirmed.

So, to answer your question directly:

* No, there are no planets currently known to the IAU that the general public is unaware of. The IAU is very transparent about their discoveries and classifications.

* However, it's entirely possible that undiscovered planets exist in our solar system or beyond. Astronomers are constantly searching for new objects in space, and it's exciting to think about what they might find!